Competing-risks mortality after radiotherapy vs. observation for localized prostate cancer: A population-based study - Abstract

PURPOSE:Contemporary patients with localized prostate cancer (PCa) are more frequently treated with radiotherapy.

However, there are limited data on the effect of this treatment on cancer-specific mortality (CSM). Our objective was to test the relationship between radiotherapy and survival in men with localized PCa and compare it with those treated with observation.

METHODS: A population-based cohort identified 68,797 men with cT1-T2 PCa treated with radiotherapy or observation between the years 1992 and 2005. Propensity-score matching was used to minimize potential bias related to treatment assignment. Competing-risks analyses tested the effect of treatment type (radiotherapy vs. observation) on CSM, after accounting to other-cause mortality. All analyses were carried out within PCa risk, baseline comorbidity status, and age groups.

RESULTS: Radiotherapy was associated with more favorable 10-year CSM rates than observation in patients with high-risk PCa (8.8 vs. 14.4%, hazard ratio [HR]: 0.59, 95% confidence interval [CI]: 0.50-0.68). Conversely, the beneficial effect of radiotherapy on CSM was not evident in patients with low-intermediate risk PCa (3.7 vs. 4.1%, HR: 0.91, 95% CI: 0.80-1.04). Radiotherapy was beneficial in elderly patients (5.6 vs. 7.3%, HR: 0.70, 95% CI: 0.59-0.80). Moreover, it was associated with improved CSM rates among patients with no comorbidities (5.7 vs. 6.5%, HR: 0.81, 95% CI: 0.67-0.98), one comorbidity (4.6 vs. 6.0%, HR: 0.87, 95% CI: 0.75-0.99), and more than two comorbidities (4.2 vs. 5.0%, HR: 0.79, 95% CI: 0.65-0.96).

CONCLUSIONS: Radiotherapy substantially improves CSM in patients with high-risk PCa, with little or no benefit in patients with low-/intermediate-risk PCa relative to observation. These findings must be interpreted within the context of the limitations of observational data.

Written by:
Abdollah F, Sun M, Schmitges J, Thuret R, Tian Z, Shariat SF, Briganti A, Jeldres C, Perrotte P, Montorsi F, Karakiewicz PI. Are you the author?
Cancer Prognostics and Health Outcomes Unit, University of Montreal Health Centre, Montreal, Canada; Department of Urology, Vita Salute San Raffaele University, Milan, Italy.

Reference: Int J Radiat Oncol Biol Phys. 2012 Feb 11. Epub ahead of print.
doi: 10.1016/j.ijrobp.2011.11.034

PubMed Abstract
PMID: 22330991